Combustion chamber



March 21, 1939. N JANEWAY 2,151,428

COMBUSTION CHAMBER Filed July 31, 1935 Patented Mar. 21, T939 UNITEDSTATES COMBUSTION CHAMBER Robert N. Janeway, Detroit, Mich.) assignor toChrysler Corporation, Detroit, Mich, a corporation of DelawareApplication July 31, 933, Serial No. 682,989

-14 Claims. (01. 123-113) J This invention relates to improvedcombustion chambers for internal combustion engine cylin- 'der heads andparticularly to an improved wall structure for such chambers.

5 More specifically, the invention relates to the provision of metalshaving different thermal conductivities at selected portions of thewalls of a combustion chamber.-

During the combustion of each charge of fuel l mixture in a chamber ofthis character the flame front of the combustion progressively travelsfrom the end of the chamber at which combustion initiates toward theopposite end of the chamber and the unburned portions of the .charge inadvance of the flame front are subjected to compression of increasingmagnitude. Such unburned portions are accordingly subjected totemperatures of increasing values. In order to prevent severedetonation, the permissible compression ratio of a combustion chamber islimited by the maximum pressure and temperature to which the finalportions of the unburned fuel are subjected at the end of eachcombustion.

I have found that by providing walls compris- 2 ing metal having arelatively high thermal conductivity throughout those portions of thechamber which, prior to ignition and after compression, contain the fuelmixture constituting the last portions of the charge to be burned,material- 0 ly higher compression of the final portions of the charge ispermitted without exceeding the maximum permissible temperature andtherefore a combustion chamber having a higher compression ratio can beused without causing objectionable detonation and the difiicultiesencountered in the use of cylinder heads composed entirely of highthermal conductive metals are eliminated for it is not necessary to bolttogether parts formed of metals having dilferent expansion coefficientssuch as, for example, a cast iron cylinder block and an aluminum alloyhead. Rapid conductivity of heat to the'cooling medium from those partsof the combustion chamber which initially contain the fuel mixture ofthe last portion of the charge to be burned is provided for withoutexcessively cooling the remaining portions of the chamber below thetemperatures required for the proper initial combustion stages.

The main objects of the invention are to pro- 60 vide improvedcombustion chamber wall structure in an internal combustion enginecylinder head which permits the compression ratio of the head to beincreased materially above that conventionally used without causingobjectionable detonation; to provide combustion chamber wall structurehaving a higher thermal conductivity at the part thereof which, prior toignition and after compression, embraces the fuel ultimately .contained'in the portion of the fuel charge that is last to be burned, than.throughout the portion of 5 the chamber in which the early stages ofcombustion take place; to provide a composite wall between the coolingmedium passage and combustion space of a cylinder head having a sectioncomprising metal of relatively high thermal conductivity located at thatportion of the chamber which registers with the cylinder bore of theengine and having a section comprising a. metal of a lower thermalconductivity in the region of the intake and exhaust valves of theengine; to provide a combustion chamber wall structure of thischaracterhaving copper or copper alloy wall sections of relatively highthermal conductivity and in which the metal of the cylinder head,preferably cast iron, constitutes the portions of the wall structure oflower thermal conductivity; to provide a copper or copper alloy plug inthe partitioning wall between the combustion space and cooling mediumpassage of a cylinder head, which registers with and extends oversubstantially the entire area of the cylinder bore; to provide a plug ofthis character having an offset portion constituting the end wall andparts of the side walls of the combustion chamber and which alsoincludes a fragmentary substantially flat rim for providing the upperboundary of that portion of the clearance space which is located betweenthe outermost position of the piston and the closest adjacent surface ofthe head of the engine where the final stages of combustion take place;and 35.

to provide a plug of this character which has its. peripheral edgeportions integrally welded to the edges of an opening in the cylinderhead structure in which the said plug is received.

Illustrative embodiments of the invention are 40 shown in theaccompanying drawing, in which:

Fig. 1 is a fragmentary transverse vertical sectional view of aninternal combustion engine having a cylinder head provided with acombustion chamber embodying my invention.

Fig. 2 is a fragmentary plan view of the inner side of the cylinder headtaken on the line II-I[ of Fig. 1 showing, in dot and dash lines, therelation of the cylinder bore and intake and exhaust valves with respectto the combustion chamber.

Fig. 3 is a fragmentary sectional view of a combustion chamber wallembodying a further modification of my invention.

In the form shown my improved combustion chamber is illustrated in acylinder head of an therein and laterally spaced longitudinal adjacentexhaust and intake valves l3 and I4 respectively. The engine is providedwith a cylinder head II in which there is formed a cooling mediumcirculating passage IS. The cylinder head ll preferably comprises castiron and it is detachably secured to the cylinder block I by bolts l1, agasket l8 being interposed between the adjacent faces of the block andhead II and I5 respectively.

The cylinder head I! includes a top wall l3 and a lower composite wall.20 comprising metals of different thermal conductivities and whichserves as a partition between the cooling medium e I and a chamber 2|provided above the cylinder bore and valves l3 and M for the receptionandcombustion of the fuel mixture. The lower wall 20 is formed to thecontour required to produce a desired combustion chamber shape, such asthat illustrated in Fig. 2, wherein the combustion chamber extends fromthe valve side of the cylinder block over a substantial portion of thecylinder bore. The composite wall 20 comprises a section 22 which isformed of the same metal as the main portion of the cylinder head andwhich is located at the valve end of the chamber and another section 23,comprising metal of a substantially higher conductivity than that of thewall section 22. The section 23 comprises a plug having a circularoutline and formed, preferably of copper or suitable alloys containingcopper or aluminum. This plug is receivable in an opening 24 ofcorresponding outline formed in the lower wall 23 of the cylinder headand it is integrally united with the remaining wall structure of thecylinder head by a suitable welding operation.

In the form shown, the opening 24 has tapering side walls 26 whichconform with correspondingly tapered side edges on the plug 23. Inmanufacturing a cylinder head of this character a ribbon 21, comprisingwelding metal, is provided between the tapering edges of the opening andplug respectively and the latter is temporarily frictionally held inplace by firmly pressing it into the opening. The cylinder head is thenpreferably heated in an atmosphere of hydrogen to a sufliciently hightemperature to fuse the metal of the welding ribbon 21 with the metal ofthe plug 23 and with the metal of the surrounding structure of thecylinder head. This welding operation has been found to be commerciallysatisfactory although it is recognized that the plug. 23-may be weldedin place by various other well known processes.

In the illustration shown, the plug 23 extends over substantially theentire area of the cylinder bore and it constitutes those portions ofthe wall structure of the combustion chamber 2| which, after the fuelcharge is under compression and prior to ignition, embrace the fuelmixture contained in the last portions of a fuel charge to be bumed'. Inthe L head engine shown, the combustion of the last portions of thecharge to be burned takes place in the clearance space 23' between theportions of the surfaces of the top plug 23 there is a fragmentary rim23 which extends beyond the cylinder end wall 21 of the chamber and overthe remaining portion of the cylinder bore I 2 and serves as a portionof the upper boundary of the clearance space 29.

The size of the plug 23 may vary in accordance with the size and shapeof the combustion cham her but it is preferable to have the metal ofhigher conductivity, of which the plug 23 is formed-constitute thoseportions of the wall of the combustion chamber which initially embracthat part of a fuel charge which ultimately retivity, such as iron,without causing detonation.

In the form shown in Fig. 3 the combustion chamber wall 22' comprises acomposite metal structure having a section 23', substantially iden-'-tical in contour to the plug 23 of Figs 1 and 2, and formed of metalhaving a relatively high thermal conductivity, such as copper, or asuitable copper alloy or aluminum. Provided in the wall 22 is anothersection 3| comprising similar metal and provided with a threadedaperture 32 for receiving a spark plug 33. The plug 23' and section 3|are integrally united with the cast iron wall structure of the cylinderhead, preferably by hydrogen welding, as set forth above. The relativelyhigh thermal conductivity of the metal of the section 3| surrounding thethreaded shank of the spark plug rapidly conducts heat away from thelatter and transmits it to the cooling medium adjacent thereto andthereby protects the insulating material of the spark plug 33 fromexcessive temperatures.

Although but two specific embodiments of my invention are herein shownand described, it will 'be understood that various changes in the size,

shape, and arrangement of parts may be made without departing from thespirit of my invention, and it is not my intention to limit its scopeother than by the terms of the appended claims.

What I claim is:

1. In an internal combustion engine cylinder head having a coolingmedium chamber, a combustion chamber having a composite wall separatingit from said combustion chamber including a copper section having asurface exposed at the interior of said combustion chamber and anopposite surface exposed at the interior of said cooling medium chamberand a section integral with said cylinder head and comprising the samemetal as the latter, said copper section substantially providing thepart of the wall of said combustion chamber which prior to ignitionembraces the fuel mixture included in the last burned portion of acompressed fuel charge.

2. In an engine having a cylinder block provided with a cylinder borecomprising a piston swept portion and a clearance space portion, intakeand exhaust valves in said block adjacent said bore, a metal cylinderhead on said block having a cooling medium chamber therein and having acombustion chamber extending over said valves and over a portion of saidcylinder bore,

a composite wall providing a heat transmitting partition between saidcooling medium chamber and said combustion chamber and including in partthe same metal as said cylinder head and a section having oppositesurface portions exposed at the interiors of said combustion and coolingmedium chambers respectively comprising metal having a higher thermalconductivity than the metal of said head, said section providing onebounding side of said clearance space.

3. In an engine having a cylinder block provided with a cylinder bore,intake and exhaust valves in said block adjacent said bore, an ironcylinder head on said block having a cooling medium chamber therein andhaving a combustion chamber extending over said valves and over.aportion of said cylinder bore and comprising a wall having portionsdisposed transversely of the axis of said bore and other portionsextending substantially in the general direction of the length of saidbore respectively, said wall providing a heat transmitting partitionbetween said cooling medium chamber and said combustion chamberincluding an iron portion formed integrally with said cylinder head andhaving a 'the interiors of said combustion and cooling chambersrespectively and having its edge portions integrally united with themetal surrounding the latter and providing parts of both of saidcombustion chamber wall portions respectively.

4. In an engine including a cylinder block having a cylinder boreprovided with a piston, intake and exhaust valves in said block adjacentsaid cylinder bore, a cylinder head on said block having a coolingmedium chamber and having a combustion chamber extending over saidvalves and over only a portion of said bore, a composite wall providinga heat transmitting partition between said cooling medium and combustionchambers and comprising sections of metal having different thermalconductivities, the section of metal of higher thermal conductivitybounding the top and sides of the portion of said combustion chamberextending over said bore and having an offset flange extending over theremaining portions of said bore and located in close proximity to saidpiston when in its outermost position for providing a limited clearancespace and having opposite surface portions exposed at the interiors ofsaid combustion and cooling medium chambers respectively.

5. In an engine including a cylinder block having a cylinder boreprovided with a piston,

intake and exhaust valves in said block adjacent said cylinder bore, acylinder head on said block having a cooling medium chamber and having acombustion chamber extending over said valves and over only a portion ofsaid bore, a composite wall providing a heat transmitting partitionbetween said cooling medium and combustion chambers and comprising aniron structure having an opening provided with a copper plug havingoppositeside surface portions exposed at the interiors of saidcombustion and cooling medium chambers respectively, said plugconstituting the top and side walls of the portion of said combustionchamber extending over said bore and having an oifset flange extendingover the remaining portion of said bore for providing the outer boundaryof the clearance space normally provided adjacent said piston when inits outermost position.

6. In an engine having a cylinder block provided with a cylinder bore, ametal cylinder head on said block having a cooling medium chambertherein and having a combustion chamber extending over a portion of saidcylinder bore comprising a composite wall having portions disposedtransversely of the axis of said bore and other portions extending inthe general direction thereof respectively, intake and exhaust valves insaid engine registering with a portion of said com-.

bustion chamber, said composite wall providing a heat transmittingpartition between said cool ing medium chamber and said combustionchamber and including in part the same metal as said cylinder .head anda section comprising metal having a higher thermal conductivity than themetal of said head, said section including parts of both of said wallportions and being located in the region of the projected area of theouter end of said bore and having opposite surface portions exposed atthe interiors of said combustion and cooling medium-chambersrespectively;

'7. An engine having a cylinder block provided with a cylinder bore, aniron cylinder head on said block having a cooling medium chamber thereinand having a combustion chamber extending over a portion of saidcylinder bore, intake and exhaust valves in said engine registering witha portion of said combustion chamber, a wall providing a heattransmitting partition between said cooling medium chamber and saidcombustion chamber including an iron portion formed integrally, withsaid cylinder head and having a circular opening substantiallyconcentric with and substantially equal in diameter to said cylinderbore, and a copper plug in said opening having its opposite side surfaceportions exposed at the interiors of said combustion and cooling mediumchambers respectively and having its edge portions integrallyunited'with the metal surrounding the latter.

8. In an engine including a cylinder block having a cylinder boreprovided with a piston, a cylinder head on said block having a coolingmedium chamber and having a combustion chamber therein extending overonly a portion of said bore, intake and exhaust valves in said engineregistering with a portion of said combustion chamber, a composite wallproviding a heat transmitting partition between said cooling medium andcombustion chambers and comprising sections of metal having differentthermal conductivities, the section of metal of higher thermalconductivity having a surface portion exposed at the interior of saidcooling medium chamber bounding the top and sides of the portion of saidcombustion chamber extending over said bore, and having an offset flangeextending over the remaining portions of said bore and located in closeproximity to said piston when in its outermost position for providing alimited clearance space.

9. In an engine including a cylinder block having a cylinder boreprovided with a piston, a cylinder head on said block having a coolingmedium chamber and having a combustion chamber therein extending overonly a portion of said bore, intake and exhaust valves in said engineregistering with a portion of said combustion chamber, a

composite wall providing a heat transmitting parber extending over saidbore and having an 75 oflset fiange extending over the remaining portionof said bore for providing the outer boundary of the clearance spacenormally provided adjacent the said piston when in its outermostposition.

10. In an engine having a cylinder block provided with a cylinder borehaving a piston swept portion and a clearance space portion, a cylinderhead comprising a cooling medium chamber, a combustion chamber having aportion extending over and an adjacent portion extending laterally fromsaid bore, said combustion chamber having a'compositewall separating itfrom said cooling medium chamber including metals of different thermalconductivities, the section of said wall defining a major portion of oneboundary of said clearance space comprising the metal of higher thermalconductivity and having a surface of said metal of higher conductivityexposed'at the inan no; 2,31,11,23.

defining a major portion of one boundary of said clearance space andhaving surface portions exposed at the interiors of said combustion andcooling medium chambers respectively.

12. In an engine having a cylinder block provided with a cylinder borecomprising a piston swept portion and a clearance space portion, acylinder head comprising a cooling medium chamber, a combustion chamberhaving a portion exsection and a section integral with said cylinderhead and comprising the same metal as the latter, said copper sectiondefining a major portion of one boundary of said clearance space andhaving a surface portion exposed at the interior of said cooling medium.

13. In an engine having a cylinder blocl: provided with a cylinder borecomprising a clearance space portion and a piston swept portion having apiston therein, a cooling medium, a combustion chamber having a portionextending over said bore, said clearance space being bounded on one sideby said piston when the latter is substantially at its top dead centerposition, .said combustion chamber having a composite wall separating itfrom said cooling medium chamber including metals of different thermalconductivities, said clearance space being bounded on its opposite sideby a section of said wall being comprised principally of the metal ofhigher thermal conductivity and having a surface portion exposed at theinterior of said cooling medium chamber so as to produce maximum coolingeffect on that portion of a fuel charge last to burn.

14. In an internal combustion engine cylinder head, a combustion chamberhaving a composite wall including metals of different thermalconductivities, the section of said wall that prior to ignition embracesthat part of the compressed fuel charge which will be the last to burnbeing com prised throughout'its thickness of the metal of higher thermalconductivity.

ROBERT N. JANEWAY.

CERTIFICATE OF CO RREC'I'ION,

March 21,. 1939 nosssr N. .JANEWAYI.

:It is hereby-certified'that error appears in'the printed'specificatiion,cf the above numbered patent requiring correct-ionas follows: Page 1;,second column, line l0, claim 12, after "medium" and before the period,insert chamber; line 11 claim 15, after "medi\ im"- and before thecomma, insert chamber; and that the said Letters Patent should be readwith this correction therein that the same mayeonform to the record ofthe case in the Patent Office Signed and sealed this th day of May, a.9.19 9.

(Seal) Henry Van Ar sdale Acting Gomissioner of Patents.

. said cooling medium chamber including a copper

